Personally, I'm disappointed with my experiences trying to use this feature. I purchased the Intel Realsense F200 camera recently. Which by the way was $200 after taxes and import costs since I'm in Canada. And so far, it's worked 2 or 3 times. So needless my experience has been lackluster and I regret spending the money.

I know my specs aren't the issue. I've recalibrated the camera dozens of times including using the option in settings to "improve recognition" after initial calibration. Doesn't seem to help. Whenever I restart my system and attempt to use facial sign-in it says "looking for me" and fails to recognize me 99% of the time. My face is approx 1.5 feet in front of the camera. Room lighting doesn't seem to change anything. I should also note that when calibrating my Windows Hello that it displays me in a black and white image. When using the camera in Skype the image is fine and shows in color. I've re-installed drivers several times and the latest SDK. I've read others complaining about this issue online due to some driver conflicts.

On a side note, I realise this is a known issue but I also suffer from the issue of my camera not powering on after resuming from sleep mode. I have tried the work around of adjusting power management settings in device manager of my USB ports but sadly that changed nothing for me.

So far, this $200 purchase was a complete waste of money for me. I get it's all new technology and there's the risk nothing will work properly but I did expect it to work at least 60% of the time. I'm hoping that some new drivers from Intel will be released soon to fix some of these bugs soon.

I'm using iris scan on a 950XL. When "Hello" fails to recognize me, it tells me to use my PIN to log in. However when I swipe up to access the PIN pad, I'm already in, NO PIN REQUIRED. UPDATE: The reason there was no PIN pad was that my login requirements had defaulted to "Password required every fifteen minutes" instead of my usual selection of: Every time. The result was that the iris scanner wanted a password every time but the PIN pad only required it every fifteen minutes. So if the iris scanner is selected the PIN requirement should default to "Every Time". Otherwise the fancy pants iris scanner is pretty well redundant.

Using the iris scanner on my 950xl and mostly it works quite well considering it's still in beta.

One thing I had a couple of times though was this : At night the phone is set to silent and charges wireless when I sleep. I had a couple of times when in the morning I got the message that windows hello was blocked due too many failed attempts and it had to be unlocked via pin.

I realise a few times that hello stop to work for no reason on my Lumia 950.
the symptoms are: no red light and no information showing on the lock screen that the phone is trying to recognise me.
Today this happened to me when I took a picture without unlocking the phone and then tried to view the pictures by pressing the photo icon which requested me to log in.
Hello failed to recognise me or I was just impatient and unlocked the phone manually by entering my code.
Now Hello will not work anymore (see symptoms above) and a restart of the phone is required to make it available again. (I did not check if disabling and re-enabling hello would make it work again.)
I was able to reproduce this a few times.
Step used:
(while the phone is locked)
Press phone power to wake it up.
Press Camera button to access camera
take picture
Press small picture icon to access
type View collection
log in to phone. (with hello or pin code).
Lock the screen and try to unlock it. Hello doesn't work anymore.

I'm using iris scan on a 950XL. When "Hello" fails to recognize me, it tells me to use my PIN to log in. However when I swipe up to access the PIN pad, I'm already in, NO PIN REQUIRED. UPDATE: The reason there was no PIN pad was that my login requirements had defaulted to "Password required every fifteen minutes" instead of my usual selection of: Every time. The result was that the iris scanner wanted a password every time but the PIN pad only required it every fifteen minutes. So if the iris scanner is selected the PIN requirement should default to "Every Time". Otherwise the fancy pants iris scanner is pretty well redundant.

I created a new topic because I was having the same issue. Nice to see that you got it resolved. Now I got it resolved thanks to you. Thanks for clarifying the solution. Take care.

How does it fail: in menu Settings > Accounts > Sign-in options I click configure finger print, than click "Start", scan my finger and it crashes - it says "something went wrong, please close Windows Hello and try again".
So I wonder if anyone has clue how to solve the issue.